$ { \left[\begin{array}{r}{-2} \\ {-2} \\ {1}\end{array}\right]-\left[\begin{array}{r}{2} \\ {1} \\ {1}\end{array}\right] = {?} } $
Solution: To find the difference of two matrices, subtract the corresponding items between each matrix. ${\left[\begin{array}{r}{-2}-{2} \\ {-2}-{1} \\ {1}-{1}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{r}{-4} \\ {-3} \\ {0}\end{array}\right]}$